Abstract

We investigated the optical properties of the saturable absorber -diethyloxadicarbocyanine iodide incorporated in a matrix of silica-gel glass by the sol-gel technique. Absorption, emission, and fluorescence lifetime were studied as functions of the densification procedures. With respect to the liquid solutions, we observed a strong quenching of the P-isomer luminescence and an increase of the N-isomer fluorescence lifetime. These effects are ascribed to a restriction on the molecular photoisomerization rearrangement caused by the rigidity of the silica cage. Moreover, entrapping reduces intermolecular concentration effects. Finally, different from other glass-embedded dyes, both the absorption and the emission are blue-shifted by about 20 nm.